Digital squamous cell carcinoma and association with diverse high-risk human papillomavirus types.

Digital squamous cell carcinoma (SCC) presents a diagnostic challenge because of its relatively rare occurrence and mimicry of benign conditions. Although low-risk human papillomavirus (HPV) subtypes are commonly associated with benign digital verrucae, digital SCC can be associated with high-risk, oncogenic HPV subtypes. We report 7 patients, including 4 HIV-positive patients, who presented with 10 lesions of digital SCC in situ. Six of 10 lesions were typed for HPV by immunostain or polymerase chain reaction. Multiple high-risk oncogenic subtypes were found, including HPV-16, -33, -51, and -73. The majority of reports linking HPV and digital SCCs have implicated the HPV-16 subtype. This case series highlights the diversity of oncogenic HPV types that may be associated with digital SCCs. Because the high rate of recurrence of digital SCCs may be a result of persistence of oncogenic HPV at the margins of resection, aggressive treatment of individual lesions and of genital reservoirs for HPV on patients and their sexual partners is warranted.